The present invention pertains to a heating apparatus and a housing for a heating apparatus, in particular, a parking heater and/or auxiliary heater for a motor vehicle.
Heating apparatuses that are used as auxiliary heaters and/or parking heaters operate independently of the internal combustion engine of a motor vehicle equipped with the heating apparatus, wherein a fuel, in particular, the fuel of the motor vehicle, is burned in order to generate heat. The exhaust gases created during the combustion are discharged from the heating apparatus, wherein an exhaust gas branch is usually connected to the heater for transporting the exhaust gases away from the heating apparatus and emitting said exhaust gases into the surroundings.
DE 43 27 139 A1 discloses a heating apparatus for motor vehicles which contains catalytically active coated sections arranged in the housing of the heating apparatus, wherein the hot exhaust gases created during the combustion of a liquid fuel are conveyed over these catalytically active sections. This measure makes it possible to reduce the emission of harmful substances by the heating apparatus. The catalytically active sections are arranged downstream of a combustion chamber in the region of a flame tube, as well as in the region of the heat exchanger of the heating apparatus. This means that the catalytically active sections are integrated into the heating apparatus without having to perform any constructive changes on the heater. In this case, the catalytically active sections are subjected to relatively high thermal loads. The volume available for the catalyst is very limited if the volume required for the oxidation (combustion) should not be reduced.
The present invention is based on the objective of disclosing an improved embodiment of a heating apparatus of the initially described type which, in particular, has a simple design.
This objective is attained with the object of the independent claims. Advantageous embodiments form the objects of the dependent claims.
The invention, in principle, proposes to realize a one-part or one-piece housing of the heating apparatus in such a way that a catalyst shaft is integrated therein, wherein the catalyst shaft serves for accommodating at least one catalytic element, through which the exhaust gases created during the operation of the heating apparatus flow. Consequently, the housing contains a catalyst shaft and a combustion chamber shaft, in which the combustion chamber of the heating apparatus is arranged or accommodated. According to the invention, the catalyst housing and a combustion chamber housing are combined into one structural unit. Such a unit can, for example, be inexpensively manufactured in one piece, in particular, from aluminum or an aluminum alloy, by means of a die casting method. The manufacture of the housing according to the invention is, in particular, less expensive than the manufacture and assembly of separate housings for the catalyst and the combustion chamber. Particularly suitable operating conditions for the catalyst accommodated in the catalyst shaft, e.g., a monolith, can be realized due to the integration of the catalyst shaft into the housing. Since the catalyst is arranged in the vicinity of the combustion chamber, the catalyst is heated relatively fast when the heating apparatus is started such that the catalyst very rapidly reaches the required operating temperature. Due to the integration of the catalyst shaft into the housing, the shape of the catalytic element or the catalyst can be adapted to the shape of the housing, in particular, with respect to a very compact structural shape of the entire unit. In addition, the dimensions of the catalyst shaft can be easily chosen such that the catalytic element accommodated therein has a sufficient volumetric and/or surface potential. This makes it possible to prevent, in particular, intense pressure drops during the flow of the exhaust gases through the catalytic element. In addition, the assembly of the heating apparatus is very simple because the respective catalytic element can, if applicable, be installed into the heating apparatus with only slight additional expenditures, for example, with a support mat or the like. The installation of an additional holding arrangement for a separate catalyst housing is eliminated. Another important advantage of the design according to the invention can be seen in the fact that a sound insulation function is already realized in the housing due to the integration of the catalyst shaft into the housing, namely because the catalytic element acts as a sound absorber while the exhaust gas flows through the catalyst shaft.
According to one additional development, the catalyst shaft is arranged downstream of an exhaust gas outlet of the combustion chamber, i.e., the catalytic element accommodated in the catalyst shaft is arranged behind the combustion chamber and, in particular, a heat exchanger of the heating apparatus. Due to this measure, the exhaust gas temperatures at the inlet of the catalyst are comparatively low such that a longer service life of the catalytic element can be achieved.
Other important characteristics and advantages of the invention are disclosed in the dependent claims, the figures and the following description that refers to the figures.
It goes without saying that the previously discussed characteristics, as well as the characteristics discussed below, cannot only be utilized in the respectively described combination, but also individually or in other combinations without deviating from the scope of the present invention.
One preferred embodiment of the invention is illustrated in the figures and described in greater detail below, wherein the same reference symbols refer to identical or functionally identical or similar components.